Issue #338 occurs because the existing routines assume that any URI with an

extension is a file, and so links to TLD's ending with .pl, .au, etc., will
cause accessibility warnings. This fix attempts to distinguish between URI's
that are likely to be files versus links to domains.

src/access.c

@@ -131,6 +131,49 @@ static void MetaDataPresent( TidyDocImpl* doc, Node* node );
 static void CheckEmbed( TidyDocImpl* doc, Node* node );
 static void CheckListUsage( TidyDocImpl* doc, Node* node );
 
+/*
+    IsFilePath attempts to determine whether or not the URI indicated
+    by path is a file rather than a TLD. For example, sample.com.au might
+    be confused with an audio file.
+*/
+static Bool IsFilePath( ctmbstr path )
+{
+    const char *p = path;
+    char c;
+    typedef enum states { initial, protocol_found, slash_found, file_found } states;
+    states state = initial;
+
+    while ( ( c = *p++ ) != 0 && state != file_found )
+    {
+        switch ( state )
+        {
+            case initial:
+                if ( c == ':' )
+                    state = protocol_found;
+                break;
+
+            case protocol_found:
+                if ( c =='/' )
+                    state = slash_found;
+                break;
+
+            case slash_found:
+                if ( c =='/' )
+                    state = protocol_found;
+                else
+                    state = file_found;
+                break;
+                
+            default:
+                break;
+        }
+        
+    }
+    
+    return state == file_found || state == initial;
+}
+
+
 /*
     GetFileExtension takes a path and returns the extension
     portion of the path (if any).
@@ -163,9 +206,10 @@ static void GetFileExtension( ctmbstr path, tmbchar *ext, uint maxExt )
 static Bool IsImage( ctmbstr iType )
 {
     uint i;
-
-    /* Get the file extension */
     tmbchar ext[20];
+
+    if ( !IsFilePath(iType) ) return 0;
+
     GetFileExtension( iType, ext, sizeof(ext) );
 
     /* Compare it to the array of known image file extensions */
@@ -190,6 +234,9 @@ static int IsSoundFile( ctmbstr sType )
 {
     uint i;
     tmbchar ext[ 20 ];
+
+    if ( !IsFilePath(sType) ) return 0;
+    
     GetFileExtension( sType, ext, sizeof(ext) );
     
     for (i = 0; i < N_AUDIO_EXTS; i++)
@@ -215,6 +262,9 @@ static Bool IsValidSrcExtension( ctmbstr sType )
 {
     uint i;
     tmbchar ext[20];
+    
+    if ( !IsFilePath(sType) ) return 0;
+    
     GetFileExtension( sType, ext, sizeof(ext) );
 
     for (i = 0; i < N_FRAME_EXTS; i++)
@@ -237,6 +287,9 @@ static Bool IsValidMediaExtension( ctmbstr sType )
 {
     uint i;
     tmbchar ext[20];
+
+    if ( !IsFilePath(sType) ) return 0;
+
     GetFileExtension( sType, ext, sizeof(ext) );
 
     for (i = 0; i < N_MEDIA_EXTS; i++)